Pouch type battery case and apparatus for manufacturing the same, and pouch type secondary battery

Abstract

A pouch-type secondary battery according to an embodiment of the present invention for solving the above problems includes a cup part configured to accommodate an electrode assembly formed by stacking electrodes and separators, wherein the cup part includes: a bottom portion configured to form a bottom; an outer wall configured to form a side surface and meet the bottom portion; a punch edge configured to connect the bottom portion to the outer wall; a thickness edge configured to connect two adjacent outer walls to each other; and a corner formed by connecting the two adjacent punch edges to the thickness edge, wherein at least one of the punch edges is rounded, at least one of the thickness edge is rounded, at least one of the corner is rounded and has a curvature radius different from that of each of the punch edge and the thickness edge.

The invention claimed is: 
     
       1. A pouch-type secondary battery case comprising a cup part configured to accommodate therein an electrode assembly having stacked electrodes and separators,
 wherein the cup part comprises a bottom portion, two adjacent outer walls that each meet the bottom portion, two adjacent punch edges that respectively connect the bottom portion to the two adjacent outer walls, a thickness edge that connects the two adjacent outer walls to each other, and a corner connecting the two adjacent punch edges to the thickness edge, 
 wherein at least one of the two adjacent punch edges is rounded, the thickness edge is rounded, and the corner is rounded, and the corner has a curvature radius different from a curvature radius of each of the two adjacent punch edges and from a curvature radius of the thickness edge, 
 wherein the corner has a curvature radius that is variable and greater than the curvature radius of at least one of the two adjacent punch edges or the curvature radius of the thickness edge, and 
 wherein an apex of the corner has an aspherical shape. 
 
     
     
       2. The pouch-type secondary battery case of  claim 1 , wherein a curvature radius of the apex of the corner is greater than a curvature radius of a peripheral portion of the corner. 
     
     
       3. The pouch-type secondary battery case of  claim 1 , wherein each of the two adjacent punch edges has a curvature radius of 2 mm or less. 
     
     
       4. The pouch-type secondary battery case of  claim 1 , wherein the thickness edge has a curvature radius of 0.5 mm to 5 mm. 
     
     
       5. The pouch-type secondary battery case of  claim 1 , wherein the thickness edge has a curvature radius greater than or equal to a curvature radius of each of the punch edges. 
     
     
       6. The pouch-type secondary battery case of  claim 1 , wherein the corner is disposed within a predetermined range of distance in a length direction and a width direction of the cup part from the thickness edge and within a predetermined range of distance in a thickness direction of the cup part from each of the two adjacent punch edges. 
     
     
       7. The pouch-type secondary battery case of  claim 6 , wherein the predetermined ranges of distance in which the corner is disposed is wider as a depth of the cup part increases. 
     
     
       8. The pouch-type secondary battery case of  claim 1 , wherein a circumference of the corner in a plane that includes the two adjacent punch edges has a curved shape. 
     
     
       9. The pouch-type secondary battery case of  claim 1 , wherein a circumference of the corner in a plane that includes one of the two adjacent punch edges and the thickness edge has a curved shape. 
     
     
       10. The pouch-type secondary battery case of  claim 1 , wherein a circumference of the corner in a plane that includes the two adjacent punch edges has at least one straight line. 
     
     
       11. The pouch-type secondary battery case of  claim 1 , wherein a circumference of the corner in a plane that includes one of the two adjacent punch edges and the thickness edge has at least one straight line. 
     
     
       12. An apparatus for manufacturing a pouch-type secondary battery case, the apparatus comprising:
 a punch configured to press a pouch film so as to form a cup part having a recessed shape in the pouch-type secondary battery case, 
 wherein the punch comprises a pressing bottom portion, two adjacent pressing outer walls that each meet the pressing bottom portion, two adjacent pressing edges that respectively connect the pressing bottom portion to the two adjacent pressing outer walls, a pressing thickness portion that connects the two adjacent pressing outer walls to each other, and a pressing corner connecting the two adjacent pressing edges to the pressing thickness portion, 
 wherein the pressing corner is rounded and has a curvature radius that is variable and different from a curvature radius of each of the two adjacent pressing edges and from a curvature radius of the pressing thickness portion, and 
 wherein an apex of the pressing corner has an aspherical shape. 
 
     
     
       13. A secondary battery comprising the pouch-type secondary battery case of  claim 1 .